A common type of article carrier for passenger vehicles which allows full access to the openings of the vehicle, including the passenger side doors, rear doors, rear hatch or tailgate, is the roof mounted article carrier. The roof mounted article carrier typically comprises a roof rack assembly including two horizontal bars that are mounted at the forward and rearward portions of the vehicle roof. Various attachments are used to secure articles, such as bicycles, skis, and other types of sporting equipment, to the bars. One drawback associated with roof mounted rack assemblies is that the user must lift the articles over their head when loading and unloading the articles onto and off of the rack assembly. Thus, in many situations, the loading and unloading procedure can be difficult for a user. For example, the over head lifting of heavier or awkwardly balanced articles, such as bicycles, can be very difficult for short people and also difficult for people who do not possess sufficient strength for repeated lifting. Also, the loading and unloading of articles is more difficult where the roof of the vehicle is high off the ground, such as is the case for vans and most four wheel drive utility vehicles. Further, it is awkward to fasten the articles to the roof mounted bars if the user has difficulty reaching the fastening structure on the bars if the user is not tall enough or the vehicle roof is too high or too wide.
Accordingly, article carriers which mount to the rear of passenger vehicles have become very popular in recent years, especially in view of the increasing popularity of four wheel drive and sport utility vehicles, all of which typically have a high roof. It is well known from the prior art to releasably secure an article carrier to a receiver hitch that is mounted on the rear of a vehicle. An example of one such prior art article carrier is the receiver hitch mounted bike rack disclosed in U.S. Pat. No. 4,676,414 issued to Deguevara. A drawback with the bike rack of Deguevara, however, is that it an all rigid structure and has no pivoting mechanism to allow access to a rear opening of the vehicle.
Another type of prior art receiver hitch mounted article carrier is the vertical tilt down bike rack disclosed in U.S. Pat. No. 5,303,857 issued to Hewson. The vertical tilt down type rack includes a pivoting structure which permits the load to move straight back and down from the rear of the vehicle to facilitate loading and unloading of articles to be carried by the rack. However, this type of article carrier still does not permit complete unobstructed access to the rear of the vehicle.
Another type of prior art receiver hitch mounted article carrier is the swing away style bike rack, two examples of which are disclosed in U.S. Pat. No. 5,094,373 issued to Lovci and U.S. Pat. No. 5,454,496 issued to Sumida et al. The swing away style receiver hitch mounted bike rack designs of Lovci and Sumida et al. include a first fixed horizontal support arm mounted to the receiver hitch of the vehicle and a second horizontal support disposed on top of and pivotally connected to the outboard end of the first fixed arm. The second arm supports a vertical post that carries the load and is operable to swing the vertical post and load away from the rear of the vehicle. The swing away style bike rack designs of Lovci and Sumida et at. tend to be cumbersome in use, especially when the loads to be carried are very heavy.
Also, the swing away style rack designs of Lovci and Sumida et al. are structurally compromised by the design of the pivot or hinge mechanism that is used to connect the upper movable horizontal arm to the lower fixed horizontal arm. More particularly, in each rack design the movable arm is disposed pivotally connected to the top of the fixed arm. In such a swing arm arrangement, all the shear forces and bending moments are concentrated on the pivot axis at the bearing surface between the two arms. Thus, the pivot axis must be designed with sufficient strength in order to withstand the bending and ovalizing forces that are exerted on the pivot bearing surfaces at this point, especially when the rack is swung outward into the open and fully extended position. Over time, heavier loads will tend to cause bending of the pivot axis and/or widening or ovalizing of the bushing surfaces which, in turn, will adversely affect the smooth swinging operation of the rack. Accordingly, it would be desirable to improve the pivot or hinge mechanism of such swing away style racks such that the improved rack can easily handle heavier loads, such as for example loads including four bicycles or more, without bending or premature failure of the pivot or hinge mechanism.
Another problem common to all receiver hitch mountable racks is the tendency of undesirable wobble to develop at the point of attachment of the rack to the receiver hitch. The wobble develops as a result of the inherent tolerance differences between the hollow interior of the receiver hitch and the insertable portion of the rack. Excessive wobble movement can be a detrimental to the integrity of the loads being carried and can interfere with the loading and unloading operation The wobble problem is especially problematic for a swing away style rack since the load, in combination with the extended horizontal support arms, will create a large bending moment or torque that acts directly on the receiver hitch mounting structure. The wobble that develops in the receiver hitch can be great in the case where the rack is heavily loaded, for example, when the rack is used to carry two or more bicycles. Accordingly, a receiver hitch mountable rack design which overcomes the above noted wobble problem would also be desirable.